A future-generation communication system has been developed to be a packet service communication system in which bursty packet data is transmitted to a plurality of mobile stations. The packet service communication system is designed especially for high-speed large-data transmission and reception. To support high-speed large-data transmission and reception in the future-generation communication system, many schemes including a Hybrid Automatic Repeat reQuest (HARQ) scheme and an Adaptive Modulation and Coding (AMC) scheme have been proposed. The use of the HARQ scheme and the AMC scheme requires support of various code rates.
Along with turbo codes, block LDPC codes are under serious consideration for the future-generation communication system due to their advantages of excellent performance gain during high-speed data transmission and increased reliability of data transmission through effective correction of noise-incurred errors in a transmission channel. However, the block LDPC code has shortcomings in code rate. In view of the nature of the block LDPC code, a codeword vector has a relatively high code rate and thus the block LDPC code is not free in terms of code rate. Most of block LDPC codes proposed so far have a code rate of 1/2 and some of them have a code rate of 1/3. This limitation of the block LDPC code in code rate makes the block LDPC code unsuitable for high-speed data transmission.
Accordingly, there is a need for a technique for transmitting and receiving a signal by supporting various code rates ranging from low to high in a communication system using block LDPC codes.